1. Field of the Invention
The present invention relates to a sealing mechanism for a rotary shaft for rotating a body-to-be-rotated arranged in a chamber, and a liquid processing apparatus using the rotary shaft sealing mechanism.
2. Related Background Art
In processes for fabricating semiconductor devices, for example, cleaning processing apparatuses are used, which process semiconductor wafers (hereinafter called “wafers”) with processing liquids, such as prescribed chemical liquids, pure water, etc. to thereby remove from the wafers particles, contaminants such as organic contaminants, metal contaminants, etc., organic matters and oxide films.
As one of such cleaning processing apparatuses, the specification of Japanese Patent Application Unexamined Publication No. 42919/1986 (Patent Reference 1), for example, discloses a processing spray which comprises a drive shaft (rotary shaft) rotatably put through the bottom surface of a housing, a turn table mounted on the drive shaft in the housing with a turn table mounting ring, a carrier supported by the turn table, which supports a plurality of wafers substantially in parallel with each other, and a spray post for spraying a processing liquid to the wafers. In this processing spray, in order to prohibit a processing liquid from intruding into the rotary shaft, a labyrinth sealing structure constituted with conical ribs and conical grooves is formed between the underside of the turn table mounting ring and the upper side of the bottom surface of the housing opposed to each other.
[Patent Reference 1]
Specification of Japanese Patent Application Unexamined Publication No. 42919/1986 (Ps. 3-5, FIGS. 1 and 3)
In the labyrinth seal structure, the direction of a processing liquid is changed when the processing liquid intrudes into the rotary shaft, which hinders the processing liquid from intruding into the rotary shaft. However, a large gap is required over the part for the ribs and the grooves engaged with each other so that the turn table mounting ring and the bottom surface of the housing are not in contact with each other, which makes it difficult to perfectly prevent a processing liquid from intruding into the rotary shaft.